Currently in Italy at the Junior World Championships, Appleyard worked with the Dragons on a short-term basis from February but will now go full-time.
"We'd like to welcome Rob as a full-time member of the Newport Gwent Dragons coaching team," said Dragons Director of Rugby Robert Beale.
"Rob joins Darren Edwards' coaching team as an assistant coach with responsibilities for defence.
"He has had a huge impact on our environment since his involvement with the region and we would like to thank Joe Lydon and the WRU in enabling Rob to join the Dragons on a full-time basis from the Union and we are confident that he will make a valuable contribution to both our defence and other areas of our game moving forward."
WRU Head of Rugby Joe Lydon said:
"We have worked closely with the Dragons management team on the process of this appointment. We know Rob's ambition has been to coach at Regional level for some time now and we see this as a positive opportunity for Rob, the players and the Newport Gwent Dragons Region.
"Rob has a wealth of experience as a player and coach. This experience coupled with a fantastic work ethic and appreciation of what is needed to develop players at all levels, means Rob is and will continue to be a valued member of any coaching set-up. We wish Rob and the Dragons well for the coming season and look forward to continuing to work with Rob and the Dragons in developing talented players for Welsh rugby at all levels"